Buildings.Examples.VAVReheat.Controls
Package with controller models
Information
Extends from Modelica.Icons.VariantsPackage (Icon for package containing variants).
Package Content
| Name | Description |
|---|---|
 ControlBus
|
Empty control bus that is adapted to the signals connected to it |
 CoolingCoilTemperatureSetpoint
|
Set point scheduler for cooling coil |
 DuctStaticPressureSetpoint
|
Computes the duct static pressure setpoint |
 Economizer
|
Controller for economizer |
 EconomizerTemperatureControl
|
Controller for economizer mixed air temperature |
 FanVFD
|
Controller for fan revolution |
 MixedAirTemperatureSetpoint
|
Mixed air temperature setpoint for economizer |
 ModeSelector
|
Finite State Machine for the operational modes |
 OperationModes
|
Enumeration for modes of operation |
 PreCoolingStarter
|
Outputs true when precooling should start |
 RoomTemperatureSetpoint
|
Set point scheduler for room temperature |
 RoomVAV
|
Controller for room VAV box |
 State
|
Block that outputs the mode if the state is active, or zero otherwise |
 Examples
|
Example models to test the components |
Types and constants
type OperationModes = enumeration( occupied "Occupied", unoccupiedOff "Unoccupied off", unoccupiedNightSetBack "Unoccupied, night set back", unoccupiedWarmUp "Unoccupied, warm-up", unoccupiedPreCool "Unoccupied, pre-cool", safety "Safety (smoke, fire, etc.)") "Enumeration for modes of operation";
Buildings.Examples.VAVReheat.Controls.ControlBus
Empty control bus that is adapted to the signals connected to it
Information
This connector defines the expandable connector ControlBus that
is used to connect control signals.
Note, this connector is empty. When using it, the actual content is
constructed by the signals connected to this bus.
Extends from Modelica.Icons.SignalBus (Icon for signal bus).
Modelica definition
expandable connector ControlBus
"Empty control bus that is adapted to the signals connected to it"
extends Modelica.Icons.SignalBus;
end ControlBus;
Buildings.Examples.VAVReheat.Controls.CoolingCoilTemperatureSetpoint
Set point scheduler for cooling coil
Information
Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Temperature | TCooOn | 273.15 + 12 | Cooling setpoint during on [K] |
| Temperature | TCooOff | 273.15 + 30 | Cooling setpoint during off [K] |
Connectors
| Type | Name | Description |
|---|---|---|
| input RealInput | TSetHea | Set point for heating coil [K] |
| ControlBus | controlBus | |
| output RealOutput | TSet | Temperature set point [K] |
Modelica definition
block CoolingCoilTemperatureSetpoint "Set point scheduler for cooling coil"
extends Modelica.Blocks.Icons.Block;
import Buildings.Examples.VAVReheat.Controls.OperationModes;
parameter Modelica.SIunits.Temperature TCooOn=273.15+12
"Cooling setpoint during on";
parameter Modelica.SIunits.Temperature TCooOff=273.15+30
"Cooling setpoint during off";
Modelica.Blocks.Sources.RealExpression TSupSetCoo(
y=if (mode.y == Integer(OperationModes.occupied) or
mode.y == Integer(OperationModes.unoccupiedPreCool) or
mode.y == Integer(OperationModes.safety)) then
TCooOn else TCooOff) "Supply air temperature setpoint for cooling";
Modelica.Blocks.Interfaces.RealInput TSetHea(
unit="K",
displayUnit="degC") "Set point for heating coil";
Modelica.Blocks.Math.Add add;
Modelica.Blocks.Sources.Constant dTMin(k=1)
"Minimum offset for cooling coil setpoint";
Modelica.Blocks.Math.Max max1;
ControlBus controlBus;
Modelica.Blocks.Routing.IntegerPassThrough mode;
Modelica.Blocks.Interfaces.RealOutput TSet(
unit="K",
displayUnit="degC") "Temperature set point";
equation
connect(dTMin.y, add.u1);
connect(add.y, max1.u1);
connect(TSupSetCoo.y, max1.u2);
connect(controlBus.controlMode, mode.u);
connect(max1.y, TSet);
connect(TSetHea, add.u2);
end CoolingCoilTemperatureSetpoint;
Buildings.Examples.VAVReheat.Controls.DuctStaticPressureSetpoint
Computes the duct static pressure setpoint
Information
Extends from Modelica.Blocks.Interfaces.MISO (Multiple Input Single Output continuous control block).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Integer | nin | 1 | Number of inputs |
| AbsolutePressure | pMin | 100 | Minimum duct static pressure setpoint [Pa] |
| AbsolutePressure | pMax | 410 | Maximum duct static pressure setpoint [Pa] |
| Real | k | 0.1 | Gain of controller |
| Time | Ti | 60 | Time constant of integrator block [s] |
| Time | Td | 60 | Time constant of derivative block [s] |
| SimpleController | controllerType | Modelica.Blocks.Types.Simple... | Type of controller |
Connectors
| Type | Name | Description |
|---|---|---|
| input RealInput | u[nin] | Connector of Real input signals |
| output RealOutput | y | Connector of Real output signal |
| input RealInput | TOut | Outside air temperature |
Modelica definition
model DuctStaticPressureSetpoint "Computes the duct static pressure setpoint"
extends Modelica.Blocks.Interfaces.MISO;
parameter Modelica.SIunits.AbsolutePressure pMin(displayUnit="Pa") = 100
"Minimum duct static pressure setpoint";
parameter Modelica.SIunits.AbsolutePressure pMax(displayUnit="Pa") = 410
"Maximum duct static pressure setpoint";
parameter Real k=0.1 "Gain of controller";
parameter Modelica.SIunits.Time Ti=60 "Time constant of integrator block";
parameter Modelica.SIunits.Time Td=60 "Time constant of derivative block";
parameter Modelica.Blocks.Types.SimpleController controllerType=Modelica.Blocks.Types.SimpleController.PID
"Type of controller";
Buildings.Controls.Continuous.LimPID limPID(
controllerType=controllerType,
k=k,
Ti=Ti,
Td=Td,
initType=Modelica.Blocks.Types.InitPID.InitialState,
reverseAction=true);
protected
Buildings.Utilities.Math.Max max(final nin=nin);
Modelica.Blocks.Sources.Constant ySet(k=0.9)
"Setpoint for maximum damper position";
Modelica.Blocks.Math.Add dp(final k2=-1) "Pressure difference";
Modelica.Blocks.Sources.Constant pMaxSig(k=pMax);
Modelica.Blocks.Sources.Constant pMinSig(k=pMin);
Modelica.Blocks.Math.Add pSet "Pressure setpoint";
Modelica.Blocks.Math.Product product;
public
Modelica.Blocks.Logical.Hysteresis hysteresis(uLow=283.15, uHigh=284.15)
"Hysteresis to put fan on minimum revolution";
Modelica.Blocks.Interfaces.RealInput TOut "Outside air temperature";
protected
Modelica.Blocks.Sources.Constant zero(k=0) "Zero output signal";
public
Modelica.Blocks.Logical.Switch switch1;
equation
connect(max.u, u);
connect(ySet.y, limPID.u_s);
connect(max.y, limPID.u_m);
connect(limPID.y, product.u1);
connect(pMaxSig.y, dp.u1);
connect(pMinSig.y, dp.u2);
connect(dp.y, product.u2);
connect(pMinSig.y, pSet.u2);
connect(pSet.y, y);
connect(hysteresis.u, TOut);
connect(product.y, switch1.u1);
connect(zero.y, switch1.u3);
connect(switch1.y, pSet.u1);
connect(hysteresis.y, switch1.u2);
end DuctStaticPressureSetpoint;
Buildings.Examples.VAVReheat.Controls.Economizer
Controller for economizer
Information
This is a controller for an economizer with that adjust the outside air dampers to meet the set point for the mixing air, taking into account the minimum outside air requirement and an override for freeze protection.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Temperature | TFreSet | 277.15 | Lower limit for mixed air temperature for freeze protection [K] |
| TemperatureDifference | dT | 1 | Temperture offset to activate economizer [K] |
| VolumeFlowRate | VOut_flow_min | VOut_flow_min(min=0) | Minimum outside air volume flow rate [m3/s] |
| Real | k | 1 | Gain of controller |
| Time | Ti | Time constant of integrator block [s] |
Connectors
| Type | Name | Description |
|---|---|---|
| input RealInput | TSupHeaSet | Supply temperature setpoint for heating |
| input RealInput | TSupCooSet | Supply temperature setpoint for cooling |
| input RealInput | TMix | Measured mixed air temperature |
| ControlBus | controlBus | |
| input RealInput | VOut_flow | Measured outside air flow rate |
| input RealInput | TRet | Return air temperature |
| output RealOutput | yOA | Control signal for outside air damper |
| output RealOutput | yRet | Control signal for return air damper |
Modelica definition
block Economizer "Controller for economizer"
import Buildings.Examples.VAVReheat.Controls.OperationModes;
parameter Modelica.SIunits.Temperature TFreSet=277.15
"Lower limit for mixed air temperature for freeze protection";
parameter Modelica.SIunits.TemperatureDifference dT(min=0.1) = 1
"Temperture offset to activate economizer";
parameter Modelica.SIunits.VolumeFlowRate VOut_flow_min(min=0)
"Minimum outside air volume flow rate";
Modelica.Blocks.Interfaces.RealInput TSupHeaSet
"Supply temperature setpoint for heating";
Modelica.Blocks.Interfaces.RealInput TSupCooSet
"Supply temperature setpoint for cooling";
Modelica.Blocks.Interfaces.RealInput TMix "Measured mixed air temperature";
ControlBus controlBus;
Modelica.Blocks.Interfaces.RealInput VOut_flow
"Measured outside air flow rate";
Modelica.Blocks.Interfaces.RealInput TRet "Return air temperature";
Modelica.Blocks.Math.Gain gain(k=1/VOut_flow_min) "Normalize mass flow rate";
Buildings.Controls.Continuous.LimPID conV_flow(
controllerType=Modelica.Blocks.Types.SimpleController.PI,
k=k,
Ti=Ti,
yMax=0.995,
yMin=0.005,
Td=60) "Controller for outside air flow rate";
Modelica.Blocks.Sources.Constant uni(k=1) "Unity signal";
parameter Real k=1 "Gain of controller";
parameter Modelica.SIunits.Time Ti "Time constant of integrator block";
Modelica.Blocks.Interfaces.RealOutput yOA
"Control signal for outside air damper";
Modelica.Blocks.Routing.Extractor extractor(nin=6, index(start=1, fixed=true))
"Extractor for control signal";
Modelica.Blocks.Sources.Constant closed(k=0) "Signal to close OA damper";
Modelica.Blocks.Math.Max max
"Takes bigger signal (OA damper opens for temp. control or for minimum outside air)";
MixedAirTemperatureSetpoint TSetMix "Mixed air temperature setpoint";
EconomizerTemperatureControl yOATMix(Ti=Ti, k=k)
"Control signal for outdoor damper to track mixed air temperature setpoint";
Buildings.Controls.Continuous.LimPID yOATFre(
k=k,
Ti=Ti,
Td=60,
controllerType=Modelica.Blocks.Types.SimpleController.PI,
yMax=1,
yMin=0)
"Control signal for outdoor damper to track freeze temperature setpoint";
Modelica.Blocks.Math.Min min
"Takes bigger signal (OA damper opens for temp. control or for minimum outside air)";
Modelica.Blocks.Sources.Constant TFre(k=TFreSet)
"Setpoint for freeze protection";
Modelica.Blocks.Interfaces.RealOutput yRet
"Control signal for return air damper";
Buildings.Controls.OBC.CDL.Continuous.AddParameter invSig(p=1, k=-1)
"Invert control signal for interlocked damper";
equation
connect(VOut_flow, gain.u);
connect(gain.y, conV_flow.u_m);
connect(uni.y, conV_flow.u_s);
connect(controlBus.controlMode, extractor.index);
connect(max.y, extractor.u[Integer(OperationModes.occupied)]);
connect(closed.y, extractor.u[Integer(OperationModes.unoccupiedOff)]);
connect(closed.y, extractor.u[Integer(OperationModes.unoccupiedNightSetBack)]);
connect(max.y, extractor.u[Integer(OperationModes.unoccupiedWarmUp)]);
connect(max.y, extractor.u[Integer(OperationModes.unoccupiedPreCool)]);
connect(closed.y, extractor.u[Integer(OperationModes.safety)]);
connect(TSupHeaSet, TSetMix.TSupHeaSet);
connect(TSupCooSet, TSetMix.TSupCooSet);
connect(controlBus, TSetMix.controlBus);
connect(yOATMix.TRet, TRet);
connect(controlBus.TOut, yOATMix.TOut);
connect(yOATMix.TMix, TMix);
connect(yOATMix.TMixSet, TSetMix.TSet);
connect(yOATMix.yOA, max.u1);
connect(min.u2, conV_flow.y);
connect(min.y, max.u2);
connect(yOATFre.u_s, TMix);
connect(TFre.y, yOATFre.u_m);
connect(yOATFre.y, min.u1);
connect(yRet, invSig.y);
connect(extractor.y, invSig.u);
connect(extractor.y, yOA);
end Economizer;
Buildings.Examples.VAVReheat.Controls.EconomizerTemperatureControl
Controller for economizer mixed air temperature
Information
This controller outputs the control signal for the outside
air damper in order to regulate the mixed air temperature
TMix.
Implementation
If the control error Tmix,set - Tmix < 0,
then more outside air is needed provided that Tout < Tret,
where
Tout is the outside air temperature and
Tret is the return air temperature.
However, if Tout ≥ Tret,
then less outside air is needed.
Hence, the control gain need to switch sign depending on this difference.
This is accomplished by taking the difference between these signals,
and then switching the input of the controller.
A hysteresis is used to avoid chattering, for example if
TRet has numerical noise in the simulation, or
measurement error in a real application.
Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | k | 1 | Gain of controller |
| Time | Ti | Time constant of integrator block [s] |
Connectors
| Type | Name | Description |
|---|---|---|
| output RealOutput | yOA | Control signal for outside air damper |
| input RealInput | TRet | Return air temperature |
| input RealInput | TOut | Outside air temperature |
| input RealInput | TMix | Mixed air temperature |
| input RealInput | TMixSet | Setpoint for mixed air temperature |
Modelica definition
block EconomizerTemperatureControl
"Controller for economizer mixed air temperature"
extends Modelica.Blocks.Icons.Block;
import Buildings.Examples.VAVReheat.Controls.OperationModes;
Buildings.Controls.Continuous.LimPID con(
k=k,
Ti=Ti,
yMax=0.995,
yMin=0.005,
Td=60,
controllerType=Modelica.Blocks.Types.SimpleController.PI)
"Controller for mixed air temperature";
parameter Real k=1 "Gain of controller";
parameter Modelica.SIunits.Time Ti "Time constant of integrator block";
Modelica.Blocks.Logical.Switch swi1;
Modelica.Blocks.Logical.Switch swi2;
Modelica.Blocks.Interfaces.RealOutput yOA
"Control signal for outside air damper";
Modelica.Blocks.Interfaces.RealInput TRet "Return air temperature";
Modelica.Blocks.Interfaces.RealInput TOut "Outside air temperature";
Modelica.Blocks.Interfaces.RealInput TMix "Mixed air temperature";
Modelica.Blocks.Interfaces.RealInput TMixSet
"Setpoint for mixed air temperature";
Modelica.Blocks.Logical.Hysteresis hysConGai(uLow=-0.1, uHigh=0.1)
"Hysteresis for control gain";
Modelica.Blocks.Math.Feedback feedback;
equation
connect(swi1.y, con.u_s);
connect(swi2.y, con.u_m);
connect(con.y, yOA);
connect(swi1.u1, TMix);
connect(swi2.u3, TMix);
connect(swi1.u3, TMixSet);
connect(swi2.u1, TMixSet);
connect(feedback.u1, TRet);
connect(TOut, feedback.u2);
connect(feedback.y, hysConGai.u);
connect(hysConGai.y, swi2.u2);
connect(hysConGai.y, swi1.u2);
end EconomizerTemperatureControl;
Buildings.Examples.VAVReheat.Controls.FanVFD
Controller for fan revolution
Information
Extends from Modelica.Blocks.Interfaces.SISO (Single Input Single Output continuous control block).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | xSet_nominal | Nominal setpoint (used for normalization) | |
| Real | r_N_min | 0.01 | Minimum normalized fan speed |
| Init | initType | Modelica.Blocks.Types.Init.N... | Type of initialization (1: no init, 2: steady state, 3/4: initial output) |
| Real | y_start | 0 | Initial or guess value of output (= state) |
| Setpoint tracking | |||
| SimpleController | controllerType | .Modelica.Blocks.Types.Simpl... | Type of controller |
| Real | k | 0.5 | Gain of controller |
| Time | Ti | 15 | Time constant of integrator block [s] |
Connectors
| Type | Name | Description |
|---|---|---|
| input RealInput | u | Connector of Real input signal |
| output RealOutput | y | Connector of Real output signal |
| input RealInput | u_m | Connector of measurement input signal |
| input BooleanInput | uFan | Set to true to enable the fan on |
Modelica definition
block FanVFD "Controller for fan revolution"
extends Modelica.Blocks.Interfaces.SISO;
import Buildings.Examples.VAVReheat.Controls.OperationModes;
Buildings.Controls.Continuous.LimPID con(
yMax=1,
Td=60,
yMin=r_N_min,
k=k,
Ti=Ti,
controllerType=controllerType,
reset=Buildings.Types.Reset.Disabled)
"Controller";
Modelica.Blocks.Math.Gain gaiMea(k=1/xSet_nominal)
"Gain to normalize measurement signal";
parameter Real xSet_nominal "Nominal setpoint (used for normalization)";
Modelica.Blocks.Sources.Constant off(k=0) "Off signal";
Modelica.Blocks.Math.Gain gaiSet(k=1/xSet_nominal)
"Gain to normalize setpoint signal";
Modelica.Blocks.Interfaces.RealInput u_m
"Connector of measurement input signal";
parameter Real r_N_min=0.01 "Minimum normalized fan speed";
parameter Modelica.Blocks.Types.Init initType=Modelica.Blocks.Types.Init.NoInit
"Type of initialization (1: no init, 2: steady state, 3/4: initial output)";
parameter Real y_start=0 "Initial or guess value of output (= state)";
parameter Modelica.Blocks.Types.SimpleController
controllerType=.Modelica.Blocks.Types.SimpleController.PI
"Type of controller";
parameter Real k=0.5 "Gain of controller";
parameter Modelica.SIunits.Time Ti=15 "Time constant of integrator block";
Buildings.Controls.OBC.CDL.Logical.Switch swi;
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput uFan
"Set to true to enable the fan on";
equation
connect(gaiMea.y, con.u_m);
connect(gaiSet.y, con.u_s);
connect(u_m, gaiMea.u);
connect(gaiSet.u, u);
connect(con.y, swi.u1);
connect(off.y, swi.u3);
connect(swi.u2, uFan);
connect(swi.y, y);
end FanVFD;
Buildings.Examples.VAVReheat.Controls.MixedAirTemperatureSetpoint
Mixed air temperature setpoint for economizer
Information
Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).
Connectors
| Type | Name | Description |
|---|---|---|
| input RealInput | TSupHeaSet | Supply temperature setpoint for heating |
| input RealInput | TSupCooSet | Supply temperature setpoint for cooling |
| ControlBus | controlBus | |
| output RealOutput | TSet | Mixed air temperature setpoint |
Modelica definition
model MixedAirTemperatureSetpoint
"Mixed air temperature setpoint for economizer"
extends Modelica.Blocks.Icons.Block;
Modelica.Blocks.Routing.Extractor TSetMix(
nin=6,
index(start=2, fixed=true)) "Mixed air setpoint temperature extractor";
Modelica.Blocks.Sources.Constant off(k=273.15 + 13)
"Setpoint temperature to close damper";
Buildings.Utilities.Math.Average ave(nin=2);
Modelica.Blocks.Interfaces.RealInput TSupHeaSet
"Supply temperature setpoint for heating";
Modelica.Blocks.Interfaces.RealInput TSupCooSet
"Supply temperature setpoint for cooling";
Modelica.Blocks.Sources.Constant TPreCoo(k=273.15 + 13)
"Setpoint during pre-cooling";
ControlBus controlBus;
Modelica.Blocks.Interfaces.RealOutput TSet "Mixed air temperature setpoint";
Modelica.Blocks.Routing.Multiplex2 multiplex2_1;
equation
connect(TSetMix.u[1], ave.y);
connect(ave.y, TSetMix.u[1]);
connect(off.y, TSetMix.u[2]);
connect(off.y, TSetMix.u[3]);
connect(off.y, TSetMix.u[4]);
connect(TPreCoo.y, TSetMix.u[5]);
connect(off.y, TSetMix.u[6]);
connect(controlBus.controlMode, TSetMix.index);
connect(TSetMix.y, TSet);
connect(multiplex2_1.y, ave.u);
connect(TSupCooSet, multiplex2_1.u2[1]);
connect(TSupHeaSet, multiplex2_1.u1[1]);
end MixedAirTemperatureSetpoint;
Buildings.Examples.VAVReheat.Controls.ModeSelector
Finite State Machine for the operational modes
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| TemperatureDifference | delTRooOnOff | 1 | Deadband in room temperature between occupied on and occupied off [K] |
| Temperature | TRooSetHeaOcc | 293.15 | Set point for room air temperature during heating mode [K] |
| Temperature | TRooSetCooOcc | 299.15 | Set point for room air temperature during cooling mode [K] |
| Temperature | TSetHeaCoiOut | 303.15 | Set point for air outlet temperature at central heating coil [K] |
Connectors
| Type | Name | Description |
|---|---|---|
| ControlBus | cb | |
| output BooleanOutput | yFan | True if the fans are to be switched on |
Modelica definition
model ModeSelector "Finite State Machine for the operational modes"
Modelica.StateGraph.InitialStep initialStep(nIn=0);
Modelica.StateGraph.Transition start "Starts the system";
State unOccOff(
mode=Buildings.Examples.VAVReheat.Controls.OperationModes.unoccupiedOff,
nIn=3,
nOut=4) "Unoccupied off mode, no coil protection";
State unOccNigSetBac(
nOut=2,
mode=Buildings.Examples.VAVReheat.Controls.OperationModes.unoccupiedNightSetBack,
nIn=1) "Unoccupied night set back";
Modelica.StateGraph.Transition t2(
enableTimer=true,
waitTime=60,
condition=TRooMinErrHea.y > delTRooOnOff/2);
parameter Modelica.SIunits.TemperatureDifference delTRooOnOff(min=0.1)=1
"Deadband in room temperature between occupied on and occupied off";
parameter Modelica.SIunits.Temperature TRooSetHeaOcc=293.15
"Set point for room air temperature during heating mode";
parameter Modelica.SIunits.Temperature TRooSetCooOcc=299.15
"Set point for room air temperature during cooling mode";
parameter Modelica.SIunits.Temperature TSetHeaCoiOut=303.15
"Set point for air outlet temperature at central heating coil";
Modelica.StateGraph.Transition t1(condition=delTRooOnOff/2 < -TRooMinErrHea.y,
enableTimer=true,
waitTime=30*60);
inner Modelica.StateGraph.StateGraphRoot stateGraphRoot;
ControlBus cb;
Modelica.Blocks.Routing.RealPassThrough TRooSetHea
"Current heating setpoint temperature";
State morWarUp(mode=Buildings.Examples.VAVReheat.Controls.OperationModes.unoccupiedWarmUp,
nIn=2,
nOut=1) "Morning warm up";
Modelica.StateGraph.TransitionWithSignal t6(enableTimer=true, waitTime=60);
Modelica.Blocks.Logical.LessEqualThreshold occThrSho(threshold=1800)
"Signal to allow transition into morning warmup";
Modelica.StateGraph.TransitionWithSignal t5;
State occ( mode=Buildings.Examples.VAVReheat.Controls.OperationModes.occupied,
nIn=3)
"Occupied mode";
Modelica.Blocks.Routing.RealPassThrough TRooMin;
Modelica.Blocks.Math.Feedback TRooMinErrHea "Room control error for heating";
Modelica.StateGraph.Transition t3(condition=TRooMin.y + delTRooOnOff/2 >
TRooSetHeaOcc or occupied.y);
Modelica.Blocks.Routing.BooleanPassThrough occupied
"outputs true if building is occupied";
Modelica.StateGraph.TransitionWithSignal t4(enableTimer=false);
State morPreCoo(
nIn=1,
mode=Buildings.Examples.VAVReheat.Controls.OperationModes.unoccupiedPreCool,
nOut=1) "Pre-cooling mode";
Modelica.StateGraph.Transition t7(condition=TRooMin.y - delTRooOnOff/2 <
TRooSetCooOcc or occupied.y);
Modelica.Blocks.Logical.And and1;
Modelica.Blocks.Routing.RealPassThrough TRooAve "Average room temperature";
Modelica.Blocks.Sources.BooleanExpression booleanExpression(y=TRooAve.y <
TRooSetCooOcc);
PreCoolingStarter preCooSta(TRooSetCooOcc=TRooSetCooOcc)
"Model to start pre-cooling";
Modelica.StateGraph.TransitionWithSignal t9;
Modelica.Blocks.Logical.Not not1;
Modelica.Blocks.Logical.And and2;
Modelica.Blocks.Logical.Not not2;
Modelica.StateGraph.TransitionWithSignal t8
"changes to occupied in case precooling is deactivated";
Modelica.Blocks.MathInteger.Sum sum(nu=5);
Modelica.Blocks.Interfaces.BooleanOutput yFan
"True if the fans are to be switched on";
Modelica.Blocks.MathBoolean.Or or1(nu=4);
equation
connect(start.outPort, unOccOff.inPort[1]);
connect(initialStep.outPort[1], start.inPort);
connect(unOccOff.outPort[1], t2.inPort);
connect(t2.outPort, unOccNigSetBac.inPort[1]);
connect(unOccNigSetBac.outPort[1], t1.inPort);
connect(t1.outPort, unOccOff.inPort[2]);
connect(cb.dTNexOcc, occThrSho.u);
connect(t6.outPort, morWarUp.inPort[1]);
connect(t5.outPort, morWarUp.inPort[2]);
connect(unOccNigSetBac.outPort[2], t5.inPort);
connect(cb.TRooMin, TRooMin.u);
connect(TRooSetHea.y, TRooMinErrHea.u1);
connect(TRooMin.y, TRooMinErrHea.u2);
connect(unOccOff.outPort[2], t6.inPort);
connect(morWarUp.outPort[1], t3.inPort);
connect(cb.occupied, occupied.u);
connect(occ.outPort[1], t4.inPort);
connect(t4.outPort, unOccOff.inPort[3]);
connect(occThrSho.y, and1.u1);
connect(and1.y, t6.condition);
connect(and1.y, t5.condition);
connect(cb.TRooAve, TRooAve.u);
connect(booleanExpression.y, and1.u2);
connect(preCooSta.y, t9.condition);
connect(t9.outPort, morPreCoo.inPort[1]);
connect(unOccOff.outPort[3], t9.inPort);
connect(cb, preCooSta.controlBus);
connect(morPreCoo.outPort[1], t7.inPort);
connect(t7.outPort, occ.inPort[2]);
connect(t3.outPort, occ.inPort[1]);
connect(occThrSho.y, not1.u);
connect(not1.y, and2.u2);
connect(and2.y, t4.condition);
connect(occupied.y, not2.u);
connect(not2.y, and2.u1);
connect(cb.TRooSetHea, TRooSetHea.u);
connect(t8.outPort, occ.inPort[3]);
connect(unOccOff.outPort[4], t8.inPort);
connect(occupied.y, t8.condition);
connect(morPreCoo.y, sum.u[1]);
connect(morWarUp.y, sum.u[2]);
connect(occ.y, sum.u[3]);
connect(unOccOff.y, sum.u[4]);
connect(unOccNigSetBac.y, sum.u[5]);
connect(sum.y, cb.controlMode);
connect(yFan, or1.y);
connect(unOccNigSetBac.active, or1.u[1]);
connect(occ.active, or1.u[2]);
connect(morWarUp.active, or1.u[3]);
connect(morPreCoo.active, or1.u[4]);
end ModeSelector;
Buildings.Examples.VAVReheat.Controls.OperationModes
Enumeration for modes of operation
Modelica definition
type OperationModes = enumeration(
occupied "Occupied",
unoccupiedOff "Unoccupied off",
unoccupiedNightSetBack "Unoccupied, night set back",
unoccupiedWarmUp "Unoccupied, warm-up",
unoccupiedPreCool "Unoccupied, pre-cool",
safety "Safety (smoke, fire, etc.)") "Enumeration for modes of operation";
Buildings.Examples.VAVReheat.Controls.PreCoolingStarter
Outputs true when precooling should start
Information
Extends from Modelica.Blocks.Interfaces.BooleanSignalSource (Base class for Boolean signal sources).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Temperature | TOutLim | 286.15 | Limit for activating precooling [K] |
| Temperature | TRooSetCooOcc | Set point for room air temperature during cooling mode [K] |
Connectors
| Type | Name | Description |
|---|---|---|
| output BooleanOutput | y | Connector of Boolean output signal |
| ControlBus | controlBus |
Modelica definition
block PreCoolingStarter "Outputs true when precooling should start"
extends Modelica.Blocks.Interfaces.BooleanSignalSource;
parameter Modelica.SIunits.Temperature TOutLim = 286.15
"Limit for activating precooling";
parameter Modelica.SIunits.Temperature TRooSetCooOcc
"Set point for room air temperature during cooling mode";
ControlBus controlBus;
Modelica.Blocks.Logical.GreaterThreshold greater(threshold=TRooSetCooOcc);
Modelica.Blocks.Logical.LessThreshold greater2(threshold=1800);
Modelica.Blocks.Logical.LessThreshold greater1(threshold=TOutLim);
Modelica.Blocks.MathBoolean.And and3(nu=3);
equation
connect(controlBus.dTNexOcc, greater2.u);
connect(controlBus.TRooAve, greater.u);
connect(controlBus.TOut, greater1.u);
connect(and3.y, y);
connect(greater.y, and3.u[1]);
connect(greater1.y, and3.u[2]);
connect(greater2.y, and3.u[3]);
end PreCoolingStarter;
Buildings.Examples.VAVReheat.Controls.RoomTemperatureSetpoint
Set point scheduler for room temperature
Information
Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Temperature | THeaOn | 293.15 | Heating setpoint during on [K] |
| Temperature | THeaOff | 285.15 | Heating setpoint during off [K] |
| Temperature | TCooOn | 297.15 | Cooling setpoint during on [K] |
| Temperature | TCooOff | 303.15 | Cooling setpoint during off [K] |
Connectors
| Type | Name | Description |
|---|---|---|
| ControlBus | controlBus |
Modelica definition
block RoomTemperatureSetpoint "Set point scheduler for room temperature"
extends Modelica.Blocks.Icons.Block;
import Buildings.Examples.VAVReheat.Controls.OperationModes;
parameter Modelica.SIunits.Temperature THeaOn=293.15
"Heating setpoint during on";
parameter Modelica.SIunits.Temperature THeaOff=285.15
"Heating setpoint during off";
parameter Modelica.SIunits.Temperature TCooOn=297.15
"Cooling setpoint during on";
parameter Modelica.SIunits.Temperature TCooOff=303.15
"Cooling setpoint during off";
ControlBus controlBus;
Modelica.Blocks.Routing.IntegerPassThrough mode;
Modelica.Blocks.Sources.RealExpression setPoiHea(
y=if (mode.y == Integer(OperationModes.occupied) or mode.y == Integer(OperationModes.unoccupiedWarmUp)
or mode.y == Integer(OperationModes.safety)) then THeaOn else THeaOff);
Modelica.Blocks.Sources.RealExpression setPoiCoo(
y=if (mode.y == Integer(OperationModes.occupied) or
mode.y == Integer(OperationModes.unoccupiedPreCool) or
mode.y == Integer(OperationModes.safety)) then TCooOn else TCooOff)
"Cooling setpoint";
equation
connect(controlBus.controlMode,mode. u);
connect(setPoiHea.y, controlBus.TRooSetHea);
connect(setPoiCoo.y, controlBus.TRooSetCoo);
end RoomTemperatureSetpoint;
Buildings.Examples.VAVReheat.Controls.RoomVAV
Controller for room VAV box
Information
Controller for terminal VAV box with hot water reheat and pressure independent damper.
It was implemented according to
[Advanced Variabled Air Volume System Design Guide], single maximum VAV reheat box
control.
The damper control signal yDam corresponds to the discharge air flow rate
set-point, normalized to the nominal value.
-
In cooling demand, the damper control signal
yDamis modulated between a minimum valueratVFloMin(typically between 30% and 50%) and 1 (corresponding to the nominal value). The control signal for the reheat coil valveyValis 0 (corresponding to the valve fully closed). -
In heating demand, the damper control signal
yDamis fixed at the minimum valueratVFloMin. The control signal for the reheat coil valveyValis modulated between 0 and 1 (corresponding to the valve fully open).
Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | ratVFloMin | 0.3 | VAV box minimum airflow ratio to the cooling maximum flow rate, typically between 0.3 to 0.5 |
| Cooling controller | |||
| SimpleController | cooController | Buildings.Controls.OBC.CDL.T... | Type of controller |
| Real | kCoo | 0.1 | Gain of controller |
| Time | TiCoo | 120 | Time constant of integrator block [s] |
| Time | TdCoo | 60 | Time constant of derivative block [s] |
| Heating controller | |||
| SimpleController | heaController | Buildings.Controls.OBC.CDL.T... | Type of controller |
| Real | kHea | 0.1 | Gain of controller |
| Time | TiHea | 120 | Time constant of integrator block [s] |
| Time | TdHea | 60 | Time constant of derivative block [s] |
Connectors
| Type | Name | Description |
|---|---|---|
| input RealInput | TRooHeaSet | Setpoint temperature for room for heating [K] |
| input RealInput | TRooCooSet | Setpoint temperature for room for cooling [K] |
| input RealInput | TRoo | Measured room temperature [K] |
| output RealOutput | yDam | Signal for VAV damper |
| output RealOutput | yVal | Signal for heating coil valve |
Modelica definition
block RoomVAV "Controller for room VAV box"
extends Modelica.Blocks.Icons.Block;
parameter Real ratVFloMin=0.3
"VAV box minimum airflow ratio to the cooling maximum flow rate, typically between 0.3 to 0.5";
parameter Buildings.Controls.OBC.CDL.Types.SimpleController cooController=
Buildings.Controls.OBC.CDL.Types.SimpleController.PI "Type of controller";
parameter Real kCoo=0.1 "Gain of controller";
parameter Modelica.SIunits.Time TiCoo=120 "Time constant of integrator block";
parameter Modelica.SIunits.Time TdCoo=60 "Time constant of derivative block";
parameter Buildings.Controls.OBC.CDL.Types.SimpleController heaController=
Buildings.Controls.OBC.CDL.Types.SimpleController.PI "Type of controller";
parameter Real kHea=0.1 "Gain of controller";
parameter Modelica.SIunits.Time TiHea=120 "Time constant of integrator block";
parameter Modelica.SIunits.Time TdHea=60 "Time constant of derivative block";
Buildings.Controls.OBC.CDL.Interfaces.RealInput TRooHeaSet(
final quantity="ThermodynamicTemperature",
final unit = "K",
displayUnit = "degC")
"Setpoint temperature for room for heating";
Buildings.Controls.OBC.CDL.Interfaces.RealInput TRooCooSet(
final quantity="ThermodynamicTemperature",
final unit = "K",
displayUnit = "degC")
"Setpoint temperature for room for cooling";
Modelica.Blocks.Interfaces.RealInput TRoo(
final quantity="ThermodynamicTemperature",
final unit = "K",
displayUnit = "degC")
"Measured room temperature";
Modelica.Blocks.Interfaces.RealOutput yDam "Signal for VAV damper";
Modelica.Blocks.Interfaces.RealOutput yVal "Signal for heating coil valve";
Buildings.Controls.OBC.CDL.Continuous.LimPID conHea(
yMax=yMax,
Td=TdHea,
yMin=yMin,
k=kHea,
Ti=TiHea,
controllerType=heaController,
Ni=10) "Controller for heating";
Buildings.Controls.OBC.CDL.Continuous.LimPID conCoo(
yMax=yMax,
Td=TdCoo,
k=kCoo,
Ti=TiCoo,
controllerType=cooController,
yMin=yMin,
reverseAction=true)
"Controller for cooling (acts on damper)";
Buildings.Controls.OBC.CDL.Continuous.Line reqFlo "Required flow rate";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant cooMax(k=1)
"Cooling maximum flow";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant minFlo(k=ratVFloMin)
"VAV box minimum flow";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant conOne(k=1)
"Constant 1";
Buildings.Controls.OBC.CDL.Continuous.Sources.Constant conZer(k=0)
"Constant 0";
protected
parameter Real yMax=1 "Upper limit of PID control output";
parameter Real yMin=0 "Lower limit of PID control output";
equation
connect(TRooCooSet, conCoo.u_s);
connect(TRoo, conHea.u_m);
connect(TRooHeaSet, conHea.u_s);
connect(conHea.y, yVal);
connect(conZer.y, reqFlo.x1);
connect(minFlo.y, reqFlo.f1);
connect(cooMax.y, reqFlo.f2);
connect(conOne.y, reqFlo.x2);
connect(conCoo.y, reqFlo.u);
connect(TRoo, conCoo.u_m);
connect(reqFlo.y, yDam);
end RoomVAV;
Buildings.Examples.VAVReheat.Controls.State
Block that outputs the mode if the state is active, or zero otherwise
Information
Extends from Modelica.StateGraph.StepWithSignal (Ordinary step (= step that is not active when simulation starts). Connector 'active' is true when the step is active).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Integer | nIn | 1 | Number of input connections |
| Integer | nOut | 1 | Number of output connections |
| OperationModes | mode | Enter enumeration of mode |
Connectors
| Type | Name | Description |
|---|---|---|
| Step_in | inPort[nIn] | Vector of step input connectors |
| Step_out | outPort[nOut] | Vector of step output connectors |
| output BooleanOutput | active | |
| output IntegerOutput | y | Mode signal (=0 if not active) |
Modelica definition
model State
"Block that outputs the mode if the state is active, or zero otherwise"
extends Modelica.StateGraph.StepWithSignal;
parameter OperationModes mode "Enter enumeration of mode";
Modelica.Blocks.Interfaces.IntegerOutput y "Mode signal (=0 if not active)";
equation
y = if localActive then Integer(mode) else 0;
end State;